mam to jakos tak smiesznie *nie kompilowalem jeszcze*

#include <string>

class Date {
  friend Date operator+(const Date date, const int days);
  friend Date operator+(const Date date1, const Date date2);
  friend ostream& operator<<(ostream& stream, const Date date);

  private:
    int day;
    int month;
    int year;

    // Thank's for tip :)
    static const unsigned short int month_days[13];

  public:
    Date(int day, int month, int year);
    ~Date();
    operator+=(int days);
    operator+=(Date date);
};

Date operator+(const Date date, const int days);
Date operator+(const Date date1, const Date date2);

ostream& operator<<(ostream& stream, const Date date);